Which of the following best explains why bubbles form during a chemical reaction involving gas evolution?

• A. A solid precipitate forms and traps air within the solution.
• B. The reactants dissolve completely, leaving behind air pockets.
• C. The temperature decreases, causing dissolved gases to condense.
• D. A gas is produced as a product and escapes from the solution.

Answer: (D)

Verified step by step guidance

1. Understand that bubbles forming during a chemical reaction typically indicate the production of a gas as one of the products.
2. Recall that when a gas is produced in a liquid solution, it tends to come out of the solution because gases have lower solubility compared to liquids and solids.
3. Recognize that the gas molecules aggregate to form bubbles, which then rise through the liquid and escape into the air.
4. Eliminate incorrect options by noting that solid precipitates trapping air or reactants dissolving completely do not explain bubble formation due to gas evolution.
5. Conclude that the best explanation is that a gas is produced as a product and escapes from the solution, causing bubbles to form.